ARRAKIHS - Analysis of Resolved Remnants of Accreted galaxies as a Key Instrument for Halo Surveys

The “Analysis of Resolved Remnants of Accreted galaxies as a Key Instrument for Halo Surveys” (ARRAKIHS) space mission is an international collaborative project.

This mission is led by a consortium of over 50 researchers from 20 research institutions and universities in 10 different countries, including Spain, Switzerland, Sweden, Austria, Belgium, England and the United States.

ARRAKIHS will image 50 square degrees of the sky per year down to an unprecedented ultra-low surface brightness (SB) simultaneously in two visible bands and two infrared bands.

This survey will result in a first-of-its-kind catalog of ultra-low SB extragalactic images for a volume-limited and mass-limited sample of galaxies like the Milky Way in the nearby universe.

The defining and unique characteristic of the ARRAKIHS mission is that it will image these systems down to an unprecedented surface brightness of 31 mag/arcsec2 with a resolution of 0.8 arcsec (FWHM) in visible wavelengths, and 30 mag /arcsec2 with 1.25 arcsec resolution (FWHM) in the near infrared.

As such, ARRAKIHS will provide an unprecedented census of stellar streams and dwarf sattelite galaxies, down to the ultra-faint regime, around almost 100 Milky Way hosts.

This data will allow us to address major outstanding issues regarding the nature of dark matter and the physics of galaxy formation.Sweden is a core memeber of the ARRAKIHS mission.

This proposal outlines the activities of the Swedish node and the funding necessary to ensure all commitments can be met during Phase 0/A/B until mission adoption.